1. Field of the Invention
This invention relates to a reproduction apparatus, and more particularly to a separating device for removing a sheet from a fusing station contained within the reproduction apparatus.
2. Description of the Prior Art
Generally, in an image formation process using a recording device, for instance an electrophotographic copying machine, a visible image is formed by forming an electrostatic latent image, corresponding to a document image, with a corona charge and a light irradiation on a photosensitive member, and developing it with a toner developer containing fine thermoplastic powders. The visible image or toner image thus formed on the photosensitive member is transferred to a receiver material such as paper. The toner image is then fused, on the paper, by a conventional heat roller fusing means.
The problem with the above system is that even with rollers that have fairly good release surfaces, the paper may still wrap around a roller.
Attempts to correct the wrap-around problem have been disclosed in U.S. Patents:
No. 4,375,327, which provides a two claw system to remove the copy sheet from the rollers. However, tight controls are needed regarding the angle between the rollers and the claws to prevent damage to the fusing area of the rollers;
No. 4,870,464, which provides a separation pawl in contact with the fusing section of the rollers, this, however, creates a potential for damage to the fusing section of the rollers;
No. 4,332,457, which provides a stripping member pressed against the rollers when the copy sheet makes contact with the rollers, but again since there is contact with the fusing section of the rollers, there is a potential for damage to that section of said rollers; and
No. 4,269,594, which provides a pair of sheet deflectors for intercepting and deflecting an image support clinging to either the fuser or pressure roller. It does not, however, provide for symmetrical flexure of the sheet deflectors which is important when it is not known to which roller the sheet may stick. In addition, there isn't any contact between the deflectors and the rollers, thereby making control of the spacing between the sheet deflectors and the rollers difficult to maintain.
In addition to the potential for damage to the rollers whenever contact is made and the criticality of the spacing between the separators and the rollers, contact has a tendency to pick off toner from the rollers and deposit it in undesirable spots on the receiver.
What is needed is a reliable separating device that will not damage the rollers in the area where fusing takes place yet still separate the receiver from the rollers and not be a source of toner pick up that may later be deposited in undesirable spots on the receiver.